#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int mn=0,i=0,flag[5]={0};
    while(i<n){
        if(password[i]>='0'&&password[i]<='9'){flag[0]=1;}
        if(password[i]>='a'&&password[i]<='z'){flag[1]=1;}
        if(password[i]>='A'&&password[i]<='Z'){flag[2]=1;}
        if(password[i]=='!'||password[i]=='@'||password[i]=='#'||password[i]=='$'||password[i]=='%'||password[i]=='^'||password[i]=='&'||password[i]=='*'||password[i]=='('||password[i]==')'||password[i]=='-'||password[i]=='+'){flag[3]=1;}
    i++;
    }
    if(flag[0]!=1)mn++;
    if(flag[1]!=1)mn++;
    if(flag[2]!=1)mn++;
    if(flag[3]!=1)mn++;
    if(n<=6){return max(6-n,mn);}
    if(n>6){return mn;}
    return 0;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}